I have been racking my brain on this topic but I am trying to create a ceiling generator and I want to remove extra geometry if I have an irregular shaped room. The only thing I have been able to work out is using the mesh geometry itself and somehow utilizing the bounding box node, but then I get stuck on how I can get the difference between these two elements. How can I get the mesh I need to remove the exess geometry?

Below are the picture examples I am working on. enter image description here enter image description here

  • $\begingroup$ please don't ask "bonus questions" - this site has some "rules". One of them is: Ask only one questions. If you have more questions, just open up a new one. Thx. $\endgroup$
    – Chris
    Oct 16, 2023 at 5:46
  • $\begingroup$ I think you'ere going to have to tell us in more detail what your generator does.. why the ceiling can't be generated from the room, directly. Is it tiling, or something? $\endgroup$
    – Robin Betts
    Oct 16, 2023 at 7:59
  • $\begingroup$ Yes, it is tiling. This is an exercise I wanted to do to see if I can create a realistic model that included all the physical elements. I found the solution down below. $\endgroup$
    – Matt L.
    Oct 17, 2023 at 3:49

1 Answer 1


I figured it out! At least one way of doing it. The reason for this question was so I could remove any areas of the ceiling that I don't want to show. Like for a room that is shaped like an "L".

Room Boundary

Box to use as boolean

This shows the raw geometry before the modifier. I just took the edges from the walls I created for the room and used this mesh as my foundation for the ceiling.

This box is what I want to cut from.

Group of model to use for Boolean

I will try to explain what this does. The top half of the group creates a plane from the original mesh. This means I have a workable face to extrude from. The nodes below uses the bounding box node to create a plane that is the overall size of the mesh. I then used the boolean node to remove the portion of the bounding box mesh which leaves me with only the object that I will use to remove parts of the ceiling. This Idea came from Blender Bash's Youtube video which explains what I did in the top portion and why iit works.


Hope this will help other people. I will even leave a link to this exact file for those who want to go deeper into what I did. Is the practical, maybe not, but its been a fun project.


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